The present invention relates generally to adapters and braces for ladders. More specifically, the present invention relates to a multi-purpose adapter for ladders which enables a ladder to be safely and securely supported by a surface having a wide array of shapes and configurations.
It has been well known to employ a ladder to assist one in accessing places which are typically out of reach. Ladders have been commonly used for painting, window washing, climbing onto roofs of buildings as well as building construction. The places at which close access is desired often include an adjacent fixed support or work surface on which the ladder is typically leaned. These work surfaces often vary greatly in their size, shape and configuration thus making it very difficult to safely lean the ladder against such a surface due to a ladder's parallel rail and rung construction. It is preferred that a ladder be leaned against a flat, planar surface.
Upon leaning the ladder against a non-planar surface such as a building wall, instability often results because the ladder cannot be firmly and evenly placed on a fixed support so one or possibly both of the parallel rails of the ladder do not contact the fixed work surface. For example, a non-planar work surface may consist of the angled edge or corner of a building. Resting a ladder on such a corner of a building will cause just the uppermost rung to contact the fixed work surface thus causing the ladder to slide on the corner of the building resulting in the entire ladder shifting to one side creating a dangerous work condition.
Many attempts have been made in the prior art to stabilize a ladder against a non-uniform fixed support. For example, U.S. Pat. No. 3,715,012, issued to Perry, discloses a safety ladder brace which includes a V-shaped member affixed to the parallel side rails to contact a non-planar support surface. As a result, a ladder may be leaned against a pole or corner. Similarly, U.S. Pat. No. 5,323,875, issued to Kennett, and U.S. Pat. No. 5,012,895, issued to Santos, also provide stabilizing structures to permit ladders to lean against various surfaces. Further, U.S. Pat. Nos. 5,121,814 and 5,165,641, both issued to Southern, disclose bases to permit a ladder to be leaned against a corner wall. Still further, U.S. Pat. No. 3,828,889, issued to Rehm, discloses a multiple accessory attachment for different surfaces and U.S. Pat. No. 4,593,790, issued to Brewer et al., discloses a stabilizer which is convertible.
Many of the prior devices enable a ladder to be leaned against a work surface with a corner to prevent the rungs of the ladder to rest against the corner which would, thereby, create an unstable condition. However, not every fixed support surface is a standard 90.degree. wall corner where the edge is perpendicular to the ground. Various other fixed support surfaces are encountered when using a ladder which are often irregular, non-planar and of an odd configuration. Due to the existence of a wide array of fixed work supports, there is a demand for a multi-purpose ladder adapter which can accommodate each of these fixed work supports without requiring elaborate devices. Therefore, it is desirable for a ladder adapter to be able to easily change its configuration to quickly accommodate the fixed work support at hand. It is desirable that the ladder adapter be easily configured to the present fixed work support. Further, it is also desirable, particularly in the construction usage of ladders, that a ladder adapter be capable of contacting roofs and other building structures under, construction as well as being able to be temporarily fastened thereto for added stability and security. It is also desirable that the ladder adapter be easily manufactured at low cost as well as being easy to operate quickly in the field.